Global warming arising from the release of greenhouse gasses into the atmosphere is one of the biggest issues attracting a lot of attention in recent years. Carbon Capture and Sequestration (CCS) is one of the strategies used to capture CO2 from different emission sites and inject it into suitable geological formations. It is, however, absolutely critical for CO 2 to remain confined and not allowed to leak into vital subsurface resources. One of the conventional problems faced in sequestration projects is the degradation of Portland cement due to its exposure to supercritical CO2 under reservoir pressure and temperature. This paper gives a review on the laboratory work carried out in the recent years to understand the kinetic potential of CO2-Cement reaction, and changes in the mechanical and transport properties of cement when it is in a CO2 rich environment. The results presented in different studies were not similar due to variety of approaches used in developing different types of cements. However, almost all of these studies indicated carbonation of the cement as a self-healing process whereas degradation of the cement starts with the bi-carbonation of CaCO3. It seems that adding a suitable quantity of Pozzolanic material could be useful in enhancing the resistance of cement against CO2, although more studies are still required to confirm this conclusion.

This paper presents an experimental study on the development of normal strength Self Compacting Concrete (SCC) from uncontrolled burning of Rice Husk Ash (RHA) as a partial replacement to cement and blended fine aggregate whilst maintaining satisfactory properties of SCC. Experiments on the fresh and hardened state properties have been carried out on RHA based SCC from uncontrolled burning. The dosages of RHA are limited to 0%, 20%, 30% & 40% by mass of the total cementitious material in the concrete. The experiments on fresh state properties investigate the filling ability, the passing ability and the segregation resistance of concrete. The experiments on hardened state properties investigate the compressive and the splitting tensile strengths. The water absorption level of the concrete with changing RHA levels has also been monitored. The experimental studies indicate that RHA based SCC developed from uncontrolled burning has a significant potential for use when normal strength is desired.

This is a repository copy of Numerical modelling and shear design rules of stainless steel lipped channel sections.

No abstract

Cold-formed steel (CFS) members have been used significantly in light-gauge steel buildings due to their inherent advantages. Optimizing these CFS members in order to gain enhanced loadbearing capacities will result in economical and efficient building solutions. This research presents the investigation and results of the optimization of CFS members for flexural capacity. The optimization procedure was performed using the particle swarm optimization (PSO) method, while the section moment capacity was determined based on the effective width method adopted in EN 1993-1-3 (EC3). Theoretical and manufacturing constraints were incorporated while optimizing the CFS crosssections. In total, four CFS sections-lipped channel beam (LCB), optimized LCB, folded-flange and super-sigma-were considered in the optimization process, including new sections. The section moment capacities of these sections were also obtained through non-linear finite element (FE) analysis and compared with the EC3-based, optimized section moment capacities. The results show that, compared with a commercially available LCB with the same amount of material, the new CFS sections possess the highest section moment capacity enhancements (up to 65 %). In addition, the performance of these CFS sections when subjected to shear and web-crippling actions was also investigated using non-linear FE analysis.